Hypertension refers to a persistent elevation of arterial blood pressure.
Prevalence is 30% in the UK (defined as adults with BP >140/90 mmHg). It is higher in men than in women before 60 years of age, but equal after this point.
Hypertension is a major risk factor for MI, stroke and chronic kidney disease (CKD). It is classified into ‘stages’ to help guide management.
The majority of hypertension is essential (primary), however in a significant number of cases there may be a secondary cause or contributory factor.
NOTE: This is an evolving area. It is now thought that a greater proportion of cases of hypertension have a secondary cause. Some studies indicate primary aldosteronism is responsible for 5-15% of cases of hypertension.
Hypertension is typically asymptomatic. However, signs and symptoms may reflect underlying end-organ damage or a potential secondary cause.
Hypertension may cause progressive retinal microvascular changes.
These changes have been classified by the Keith-Wagener Barker (KWB) grades:
Grade 4 may indicate malignant hypertension requiring admission and immediate management. Recently there has been a move away from the KWB grades with a new three stage system proposed.
In the following patients underlying causes should be thoroughly excluded:
- Age < 40 years
- Reduced eGFR (suggestive of renal disease)
- Proteinuria or haematuria (suggestive of renal disease)
- Hypokalaemia and hypernatraemia (suggestive of Conn’s syndrome)
- Hypertension that is sudden onset, variable or worsening.
NICE now recommends the use of ambulatory BP measurements (ABPM) for the diagnosis of Stage 1 & 2 hypertension.
If clinic BP is 140/90 mmHg or higher, ABPM is used to confirm the diagnosis (except in Stage 3 hypertension, in which immediate treatment is initiated). With ABPM, at least two measurements an hour are taken during the patient's usual waking hours (e.g. 8 am - 10 pm). The average value of these measurements is used to confirm the diagnosis.
Management of hypertension is based upon NICE guidelines.
Lifestyle modification & patient education are important in treating hypertension.
Antihypertensive drug therapy is initiated in patients:
Hypertension is managed in a step-wise fashion. If blood pressure is not controlled with each step, medication should be reviewed to ensure that the treatment is optimal before moving onto the next step.
For people aged > 80 years, offer the same anti-hypertensive therapies as for people aged 55-80 years, however take into consideration comorbidities.
Those with renal disease and proteinuria or diabetes should target a BP of <130/80.
Hypertensive emergencies occur when high BP results in acute end-organ damage.
The term malignant (or accelerated) hypertension is typically reserved for when papilloedema is present and is defined by NICE as:
A BP >180/110 with signs of papilloedema and/or retinal haemorrhage.
It is a severe condition resulting in neurological, renal and cardiac damage, requiring admission and immediate management.
Treatment attempts to reduce BP over 24-48hrs. This is to prevent hypoperfusion. Changes may have occurred to autoregulatory mechanisms of blood pressure control. Therefore, a rapid reduction in blood pressure, even to normal levels, may result in profound organ hypoperfusion.
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